/Engine/Plugins/Runtime/MeshModelingToolset/Source/ModelingComponents/Public/Selection/BoundarySelector.h
This class allows selection of mesh boundary loops. It inherits fromFGroupTopologySelectorto leverage a lot of the selection functionality, but it uses a FMeshBoundaryLoops object rather than a FGroupTopology object to determine which loops are selectable.
class FBoundarySelector : public [FMeshTopologySelector](API\Plugins\ModelingComponents\Selection\FMeshTopologySelector)